Counterfeiting and tampering with secure documents or instruments, such as bank notes, checks, tickets, credit cards and the like, and other valuable merchandise or items is a common problem in many fields or enterprises. To prevent counterfeiting, many secure documents and other items of value include a security device or element, such as a security thread, disposed on or in the document. The security device typically includes one or more security features, such as metallic security features, magnetic security features, or luminescent security features, that authenticate the document and prevent counterfeiting and/or tampering.
To authenticate the document, many conventional security devices merely require that the existence of a single security feature be detected. Thus, counterfeiters need only recognize the security feature in a document or item and reproduce that one security feature in a counterfeit document or item such that the security feature is detectable to authenticate the counterfeit document. Advances in technology have brought even new and easier ways of identifying these security features and reproducing the valuable documents or instruments with the security device. Thus, a need exists for more covert security features that are not easily identified and reproduced.
One type of security thread includes metallic features, such as metallic graphic indicia, disposed on a carrier substrate. According to conventional chemical etching techniques, a chemical resist is printed on a metallic layer in the form of the graphical indicia, either positively or negatively, and de-metalization of the areas of the metallic layer not covered by the chemical resist causes the graphic indicia to be formed either negatively or positively by the remaining metallic layer. Security threads having only a metallic security feature, formed according to this method, do not provide adequate protection because the counterfeiter can easily recognize and reproduce the metallic graphic indicia.
Attempts have been made to combine multiple security features, such as metallic and magnetic features, to make counterfeiting more difficult. In one example, magnetic ink is used to print graphic indicia that can be read by MICR detectors. However, if magnetic ink is used to print graphic indicia on or with metallic security features, the magnetic features and metallic features are easily distinguishable and identified. A counterfeiter could recognize that both magnetic and metallic security features have been used and need to be reproduced.
Other types of security threads have also used hybrid metals or alloys to form graphic indicia having both magnetic and metallic security features. However, the hybrid metals and the process for depositing or applying the hybrid metals to form the graphic indicia is costly. Also, using hybrid metals limits the ability to vary the magnetic properties that can be used.
Accordingly, a need exists for a security device having multiple security features, such as metallic and magnetic security features, that are not easily distinguishable and recognizable upon observing the security device. A need also exists for a security device in which the security feature(s) is capable of providing machine readable encoded data, e.g., pertaining to the security device or document, in addition to detectable features for authentication of the security document. What is also needed is a method of making a magnetic/metallic security device using existing chemical etching or de-metalization techniques.